Replacing brake booster with electronic assembly

[baon3h]

I was wondering if anyone has looked into replacing the brake booster with a modern electronic assembly (such as the Bosch iBooster) that doesn't require a vacuum and runs on 12V. The iBooster is interesting because it runs without a CAN bus. You can find them used for less than USD 200 (including master cylinder).

Replacing the original brake booster is only getting more expensive and having a more affordable option would be great.

[Jack the Knife]

That's an interesting idea. I'd contact this guy, who put one in his Volvo Amazon: https://www.evcreate.com/installing-the-ibooster/

It looks like he makes custom mounting kits for people, too. There is a popular YouTuber as well who put one in his gen-1 Hummer electric restomod build because the pump for the brakes was loud and whiny.

If you do this swap, please let us know!

[Leester]

I've been exploring this for my 220SE cab with the remote brake booster. I would really like to keep it as original as possible but if the remote brake booster gives out, the cost to repair may be an issue. On top of that the current set up is a single circuit brake system seems outdated. My problem is that I (fortunately) have a manual transmission and the master cylindar for the transmission is right next to the brake MC affording little working space. This can be resolved with a newer pedal package with the clutch MC built into the clutch pedal but again, more work and expense.

Very interested in following anyone proceeding down this path.

[baon3h]

I was afraid that someone would say I'm crazy

I'll do some more research and then order the parts. It looks like the bolt pattern is close but not close enough so I'll have to design a custom bracket for the firewall. That seems doable. What I want to do next is measure the liquid displacement of the old booster when I press the brake pedal (without vacuum) to have a baseline to compare against. I'm not sure how different the stroke for the iBooster will be.

In terms of brake fluid, the OEMs recommend DOT4 for the iBooster. I assume the Mercedes recommended brake fluid was chosen to work with their brake master cylinder. What are your thoughts?

[Jack the Knife]

I was afraid that someone would say I'm crazy

I don't think anyone would fault you for wanting to have a safer car, and in my opinion, the spirit of this car is not in the brakes.

You can use DOT4 in the OEM system, many people do.

[Leester]

Baon3h, do you have a manual shift car or automatic? I think your project will be easier with an automatic transmission since the clutch MC won't be in the way. Please keep us posted and good luck. Lee

[baon3h]

Hi Leester, I have a manual but I'm not planning to change the pedal itself. The brake booster should bolt onto the firewall with an adapter. I only have the clutch reservoir next to the brake booster, there should be plenty of space.

I'm hoping that I will get the right amount of travel out of the existing brake pedal linkage to power the new booster. Am I being too optimistic?

[Leester]

"Hi Leester, I have a manual but I'm not planning to change the pedal itself. The brake booster should bolt onto the firewall with an adapter. I only have the clutch reservoir next to the brake booster, there should be plenty of space."

Interesting - in my 63 I have both the clutch reservoir and the clutch MC next to brake booster. My "research" to date consists of looking at a couple of U-tube videos so I think you're deeper into this than I. I agree that you will have to fabricate an adapter and maybe that will resolve any clearance issues in the engine compartment.

"I'm hoping that I will get the right amount of travel out of the existing brake pedal linkage to power the new booster. Am I being too optimistic?"  I can't help you with that question. I'm almost always too optimistic about everything I undertake.

Good luck and obviously you have one follower and supporter.

Lee

[baon3h]

And so it begins! The booster is a GEN2 from a Tesla Model Y and has about the same bolt pattern (square, 72mm). I hope that it will bolt on with minor modifications (probably a spacer).

Brake line ports are on the opposite side of the cylinder. I noticed that my cylinder has three outputs (I think 2 are common on a 280SL). I will get a splitter to hook up the front brake lines.

Next up, electrical test on the bench.

[Jack the Knife]

And so it begins! The booster is a GEN2 from a Tesla Model Y and has about the same bolt pattern (square, 72mm). I hope that it will bolt on with minor modifications (probably a spacer).

Brake line ports are on the opposite side of the cylinder. I noticed that my cylinder has three outputs (I think 2 are common on a 280SL). I will get a splitter to hook up the front brake lines.

Next up, electrical test on the bench.

It's nice to see someone immediately jump into R&D rather than admiring the issue. Looking forward to your progress

[Leester]

Baon: Your picture suggests to me that your project just got easier. Your have a later model (post 1963) with the booster at the firewall. I have an early model with a remote booster behind the left side headlight.

That's why all you have for the clutch is the fluid reservoir - the clutch MC is built into the clutch pedal under the dash.

Your picture also shows the problem I would encounter. In my case, the clutch MC is just to the right (as seen from sitting in the driver's seat) of the brake booster. Your picture shows the electric brake booster with a chunk of its body that extends to the right which, I'm sure would interfere with the operation my clutch pedal and clutch MC.

All that said, I agree with JtK that its nice to see someone jump in and move on the project. You already have the dual circuit brake system so I might quibble with replacing the very common stock booster but hey, go for it!

I'll try to post a picture of my early single circuite brake system set up which will explain my concerns with converting my system to electric booster. Good luck with this project!  Lee   

[MikeSimon]

The power brakes run on vacuum. Many modern cars with turbo engines and CDI lack intake manifold vacuum ( the source for the brake booster) these cars have a secondary vacuum pump, driven by belt, directly from the camshaft or by electric motor. Wonder if this would make a possible conversion.

[Leester]

Interesting point Mike. I would add diesels to your list (fondly recalling my 300SD). What both Baon and I are trying to do (albeit for different reasons) is eliminate the vacuum brake booster.

I will let Baon weigh in on what might work in his case. In my case, which is much different than his, I have the clutch push rod and brake booster push rod about three or four inches apart on the fire wall.  The only solution I have come up with to date is changeing the old style pedals in which the clutch pedal just pushes a rod through the firewall to the clutch MC over to the new style pedals in which the clutch MC is built into the clutch pedal. On the newer style pedals, as with I think all W113 cars, the only clutch equipment in the engine bay is the clutch fluid reservoir.

I'm trying to think of a way to use your suggestion but I keep bumping into that darn clutch push rod and MC in the engine bay. But I'll keep your suggestion in mind as I pursue options.

When I replied to Baon, I didn't realize he had the fire wall mounted booster and I thought we were both dealing with remote brake boosters.

I'll try to get a photo up tomorrow.   

[baon3h]

Your picture shows the electric brake booster with a chunk of its body that extends to the right which, I'm sure would interfere with the operation my clutch pedal and clutch MC.

You can flip the master cylinder by 180 degrees on these so it might give you just enough space. Part numbers for the booster I have are 1188671-00-A and 1188671-00-B.

[mauro12]

Guys , my mechanic tested my brake booster with a vacuum gauge and at idle shows a vacuum of 500mmhg or 0.6 bar. He said it is still within specs. When you press the brakes , it goes down to 400mmhg or 0.5 bar . What is your assesment on that ? thank you

[Raymond]

Baon, I'll be anxiously awaiting the results.  How will you address the fluid level sensors?